Dietary fiber alters gut bacteria, supports gastrointestinal health

ScienceDaily (June 28, 2012) — A University of Illinois study shows that dietary fiber promotes a shift in the gut toward different types of beneficial bacteria. And the microbes that live in the gut, scientists now believe, can support a healthy gastrointestinal tract as well as affect our susceptibility to conditions as varied as type 2 diabetes, obesity, inflammatory bowel disease, colon cancer, and autoimmune disorders such as rheumatoid arthritis.

See Also:Health & MedicineGastrointestinal ProblemsNutritionDiet and Weight LossPlants & AnimalsFoodBacteriaLife SciencesReferenceSouth Beach dietWhole grainBranFecal incontinence

As these microbes ferment fiber in the intestine, short-chain fatty acids and other metabolites are produced, resulting in many health benefits for the host, said Kelly Swanson, a U of I professor of animal sciences.

"When we understand what kinds of fiber best nurture these health-promoting bacteria, we should be able to modify imbalances to support and improve gastrointestinal health," he said.

This research suggests that fiber is good for more than laxation, which means helping food move through the intestines, he added.

"Unfortunately, people eat only about half of the 30 to 35 grams of daily fiber that is recommended. To achieve these health benefits, consumers should read nutrition labels and choose foods that have high fiber content," said Swanson.

In the placebo-controlled, double-blind intervention study, 20 healthy men with an average fiber intake of 14 grams a day were given snack bars to supplement their diet. The control group received bars that contained no fiber; a second group ate bars that contained 21 grams of polydextrose, which is a common fiber food additive; and a third group received bars with 21 grams of soluble corn fiber.

On days 16-21, fecal samples were collected from the participants, and researchers used the microbial DNA they obtained to identify which bacteria were present. DNA was then subjected to 454 pyrosequencing, a "fingerprinting" technique that provides a snapshot of all the bacterial types present.

Both types of fiber affected the abundance of bacteria at the phyla, genus, and species level. When soluble corn fiber was consumed, Lactobacillus, often used as a probiotic for its beneficial effects on the gut, increased. Faecalibacterium populations rose in the groups consuming both types of fiber.

According to Swanson, the shifts in bacteria seen in this study--which occurred when more and differing types of fiber were consumed--were the opposite of what you would find in a person who has poor gastrointestinal health. That leads him to believe that there are new possibilities for using pre- and probiotics to promote intestinal health.

"For example, one type of bacteria that thrived as a result of the types of fiber fed in this study is inherently anti-inflammatory, and their growth could be stimulated by using prebiotics, foods that promote the bacteria's growth, or probiotics, foods that contain the live microorganism," he said.

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Rare Drug-Resistant Bacteria Spotted in U.S. Hospital

HealthDay – 4 hrs ago THURSDAY, June 21 (HealthDay News) -- A rare type of deadly bacteria was found in two patients in a Rhode Island hospital in 2011, but swift treatment and infection control measures stopped any further spread, a new government report shows.

The bacterium -- called New Delhi metallo-beta-lactamase (NDM)-producing Klebsiella pneumoniae -- is highly resistant to antibiotics and easily spread. It is rare in the United States, but more common in areas including India, Pakistan, Cambodia and other Asian countries.

"These people had the bacteria in their body, but fortunately it was not causing an infection anywhere," said lead researcher Dr. Leonard Mermel, medical director of the department of epidemiology and infection control at Rhode Island Hospital, in Providence.

The bacteria were isolated in one patient's urine sample and in another patient's fecal sample, but nowhere else in their body.

Infections with this strain of bacteria, however, can be deadly and there are few treatment options, Mermel said.

Where the bacteria is endemic, its growth is spurred on by several conditions, he said.

"In many parts of the developing world, you can just walk into a pharmacy and get antibiotics without a prescription, so there is widespread antibiotic use," Mermel said.

This ease of getting antibiotics coupled with poor sanitation promotes bacteria growth and creates a "perfect storm" for the development of resistant strains of bacteria, he said.

The report was published in this week's issue of Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention.

The first patient was hospitalized in Rhode Island, after being hospitalized in her native Cambodia and treated with antibiotics. In the U.S. hospital, infection was discovered and she received a wide range of antibiotics. However, only partial infection control measures were taken. Eventually, the infection spread to another patient in the same ward.

At that time, stronger infection control measures were taken and no other patients were infected.

Dr. Marc Siegel, an infectious disease expert and associate professor of medicine at NYU Langone Medical Center in New York City, said that "this is not an epidemic, but it is eyebrow-raising. This bacteria is very problematic and highly resistant to antibiotics."

So far, this hasn't become epidemic, he said. "These are isolated cases," he said. "This is another resistant bacteria -- an ultra-resistant bacteria."

Siegel doesn't expect to see this bacteria become common in the United States.

"I don't think it's going to take hold here," he said. "I am concerned more about the importing of this bacteria. We are going to be seeing more cases."

The goal is to control the bacteria with infection precautions, including patient isolation, Siegel said.

This case drives home several points, he noted. "We need better sanitation in hospitals. We need to be vigilant in searching for these types of bacteria. We really could use more antibiotics. There have been almost no new antibiotics in the past decade."

It's the tip of the iceberg, Siegel said. "The iceberg is the developing of resistant bacteria, but this bacteria is not likely to spread in the near future, but it is of concern."

The overuse of antibiotics adds to the creation of these resistant strains, he added.

More information

For more on drug-resistant bacteria, visit the U.S. Centers for Disease Control and Prevention.

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Western diet changes gut bacteria and triggers colitis in those at risk

ScienceDaily (June 13, 2012) — Certain saturated fats that are common in the modern Western diet can initiate a chain of events leading to complex immune disorders such as inflammatory bowel diseases (IBD) in people with a genetic predisposition, according to a study to be published early online in the journal Nature.

See Also:Health & MedicineDiet and Weight LossGastrointestinal ProblemsObesityCholesterolColitisImmune SystemReferenceSaturated fatTransplant rejectionColostrumIrritable bowel syndrome

The finding helps explain why once-rare immune-mediated diseases have become more common in westernized societies in the last half century. It also provides insights into why many individuals who are genetically prone to these diseases are never affected and how certain environmental factors can produce inflammation in individuals already at risk.

Researchers at the University of Chicago found that concentrated milk fats, which are abundant in processed and confectionary foods, alter the composition of bacteria in the intestines. These changes can disrupt the delicate truce between the immune system and the complex but largely beneficial mix of bacteria in the intestines. The emergence of harmful bacterial strains in this setting can unleash an unregulated tissue-damaging immune response that can be difficult to switch off.

"This is the first plausible mechanism showing step-by-step how Western-style diets contribute to the rapid and ongoing increase in the incidence of inflammatory bowel disease," said study author Eugene B. Chang, MD, the Martin Boyer Professor of Medicine at the University of Chicago. "We know how certain genetic differences can increase the risk for these diseases, but moving from elevated risk to the development of disease seems to require a second event which may be encountered because of our changing lifestyle."

The researchers worked with a mouse model that has many of the characteristics of human IBD. Genetically deleting a molecule, interleukin 10, which acts as a brake on the immune system's response to intestinal bacteria, caused about 25 percent of mice to develop colitis when fed a low-fat diet or a diet high in polyunsaturated fats. But when exposed to a diet high in saturated milk fats, the rate of disease development within six months increased to more than 60 percent. In addition, the onset, severity and extent of colitis were much greater than that observed in mice fed low-fat diets.

Why would milk fat -- a powdered substance that remains when fat has been separated from butter and dehydrated -- trigger inflammation when polyunsaturated fat did not? The researchers traced the answer to the gut microbiome, the complex mix of hundreds of bacterial strains that reside in the bowels.

The researchers found that an uncommon microbe called Bilophila wadsworthia was preferentially selected in the presence of milk fat. Previous studies had found high levels of B. wadsworthia in patients with appendicitis and other intestinal inflammatory disorders, including inflammatory bowel disease.

"That piqued our interest," Chang said. "These pathobionts, which are usually non-abundant, seem to be quite prominent in these diseases."

Indeed, while Bilophila wadsworthia levels were almost undetectable in mice on a low-fat or unsaturated-fat diet, the bacteria made up about 6 percent of all gut bacteria in mice fed a high milk-fat diet.

"Here we show how the trend in consumption of Western-type diets by many societies can potentially tip the mutualistic balance between host and microbe to a state that favors the onset of disease," Chang said.

As its name implies, Bilophila wadsworthia has an affinity for bile, a substance produced by the liver and released into the intestines to help break down ingested fats. Milk fats are particularly difficult to digest and require the liver to secrete a form of bile that is rich in sulfur. B. wadsworthia thrives in the presence of sulfur. So when the bile created to dissolve milk fats reaches the colon, it enables wadsworthia to blossom.

"Unfortunately, these can be harmful bacteria," Chang said. "Presented with a rich source of sulfur, they bloom, and when they do, they are capable of activating the immune system of genetically prone individuals."

The byproducts of B. wadsworthia's interaction with bile also can amplify the effect. They serve as "gut mucosal barrier breakers," said Suzanne Devkota, PhD, a member of Chang's laboratory and first author of the study. "By increasing the permeability of the bowel, they enhance immune-cell infiltration, and that can induce tissue damage."

Much of the recent progress in understanding the biology of inflammatory bowel disease has focused on gene variants that can increase risk, beginning with the discovery in 2001 of Nod2 by researchers at the University of Chicago. But the new study puts the focus on changing environmental factors that might trigger the disease in high-risk patients.

"Right now we can't do much about correcting genes that predispose individuals to increased risk for these diseases," Chang said, "and while we could encourage people to change their diets, this is seldom effective and always difficult."

"However, the balance between host and microbes can be altered back to a healthy state to prevent or treat these diseases," he added. "In essence, the gut microbiome can be 're-shaped' in sustainable and predictable ways that restore a healthy relationship between host and microbes, without significantly affecting the lifestyles of individuals who are genetically prone to these diseases. We are testing that right now."

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Caesarean section delivery may double risk of childhood obesity: May be due to different gut bacteria

ScienceDaily (May 23, 2012) — Caesarean section delivery may double the risk of subsequent childhood obesity, finds research published online in the Archives of Disease in Childhood.

See Also:Health & MedicinePregnancy and ChildbirthObesityGynecologyDiet and Weight LossInfant's HealthChildren's HealthReferenceBreech birthBirth weightBody mass indexNutrition and pregnancy

Caesarean section delivery has already been linked to an increased risk of subsequent childhood asthma and allergic rhinitis, and around one in three babies born in the US is delivered this way.

The authors base their findings on 1255 mother and child pairs, who attended eight outpatient maternity services in eastern Massachusetts, USA between 1999 and 2002.

The mums joined the study before 22 weeks of pregnancy, and their babies were measured and weighed at birth, at six months, and then at the age of three, when the child's skinfold thickness, a measure of body fat, was also assessed.

Out of the 1255 deliveries, around one in four (22.6%; 284) were by caesarean section, and the remainder (77.4%; 971) were vaginal deliveries.

Mums who delivered by c-section tended to weigh more than those delivering vaginally, and the birthweight for gestational age of their babies also tended to be higher. These mums also breastfed their babies for a shorter period.

But irrespective of birth weight, and after taking account of maternal weight (BMI) and several other influential factors, a caesarean section delivery was associated with a doubling in the odds of obesity by the time the child was 3 years old.

Just under 16% of children delivered via c-section were obese by the age of 3 compared with 7.5% of those born vaginally.

Children delivered by c-section also had higher BMI and skinfold thickness measurements by the age of 3.

The researchers speculate that one possible explanation for their findings is the difference in the composition of gut bacteria acquired at birth between the two delivery methods.

They highlight previous research showing that children born by c-section have higher numbers of Firmicutes bacteria and lower numbers of Bacteroides bacteria in their guts. These two groups make up the bulk of gut flora.

Other research has also suggested that obese people have higher levels of Firmicutes bacteria.

It may be that gut bacteria influence the development of obesity by increasing energy extracted from the diet, and by stimulating cells to boost insulin resistance, inflammation, and fat deposits, say the authors.

"An association between caesarean birth and increased risk of childhood obesity would provide an important rationale to avoid non-medically indicated caesarean section," write the authors.

Mums who choose this delivery option should be made aware of the potential health risks to her baby, including the possibility of obesity, they say.

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Flesh-Eating Bacteria No Cause for Panic, Experts Say

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Georgia flesh-eating bacteria patient breathing on own: father

Reuters – 16 mins ago ATLANTA (Reuters) - A Georgia graduate student fighting a rare flesh-eating bacterial infection she contracted after being injured in a zip-line accident nearly three weeks ago is breathing on her own without the help of a ventilator, her father said.

The struggle to save 24-year-old Aimee Copeland from necrotizing fasciitis - a bacterial infection that can destroy muscles, skin and tissue - has been chronicled by her father, Andy Copeland, in a blog on the university's website.

"She has been off of the ventilator for over 10 hours," Andy Copeland wrote late on Sunday. "In other words, she is breathing completely on her own! How cool is that?"

Copeland, a student at West Georgia University, slashed her calf when the zip-line snapped May 1 along the Little Tallapoosa River near Carrollton, Georgia. Emergency room doctors closed the wound with 22 staples and released Copeland, but she was diagnosed with the infection after her conditioned worsened.

Surgeons amputated Copeland's left leg at the hip. Last week, she mouthed, "Let's do this" when told her hands and remaining foot would have to be amputated, her father wrote on Friday.

It is unclear from Andy Copeland's postings whether the additional amputations had already occurred. A hospital spokeswoman has declined to comment on the woman's condition.

In his Sunday night posting, Andy Copeland said he was reducing the time he spends on media interviews.

"Two of my most important responsibilities are to pray for and provide financial support for my family," he wrote. "Everything else, including blog posting, organizing blood drives and conducting media interviews is secondary."

Different bacteria can cause necrotizing fasciitis. Health experts say the "flesh-eating" infection is not communicable.

Two cases of flesh-eating infections have been reported recently in South Carolina as well.

A new mother of twins, Lana Kuykendall, 36, was admitted to Greenville Memorial Hospital on May 11, days after giving birth, with a painful spot on her leg that was ultimately diagnosed as necrotizing fasciitis.

Her brother, Brian Swaffer, said Kuykendall had undergone at least seven operations, was sedated, and only opened her eyes "a little bit, at times."

A former South Carolina fire chief, Glenn Pace, told a local television station he had been battling a flesh-eating bacteria since early April and had three surgeries on his foot.

A 1996 report from the U.S. Centers for Disease Control and Prevention estimated there were 500 to 1,500 cases of necrotizing fasciitis annually in the United States, with about 20 percent of them fatal. The National Necrotizing Fasciitis Foundation has said that estimate is probably low.

(Reporting by David Beasley and Harriet McLeod; Editing by Cynthia Johnston)

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